Table 2. Genotype distributions of the human KCNIP1 gene insertion/deletion polymorphism in the study populations.

Genotype	AF (N=105)	NSR (N=422)	P-value*
Genotype distribution in the stage II population
D/D†	41	261	0.289/0.527
D/I, I/I†	64	161	2.47 × 10−6

Genotype	AF (N=1,022)	NSR (N=2,025)	P-value*
Genotype distribution in the stage III population
D/D	426	1,217	0.514/0.867
D/I, I/I	596	808	5.38 × 10−23

Genotype	AF (N=275)	NSR (N=546)	P-value*
Genotype distribution in subjects from different geographic areas
D/D	104	322	0.357/0.234
D/I, I/I	171	224	1.23 × 10−9

AF, atrial fibrillation; D, deletion allele (∼4,470 bp) in the first intron of the human KCNIP1 gene; I, insertion allele; NSR, normal sinus rhythm; SNP, single-nucleotide polymorphism.

The insertion (or gain) and deletion denote presence (insertion) and absence (deletion) of the same ∼4 kb chromosomal segment in the intron 1 of the KCNIP1 gene, respectively. This is a diallelic variant (same as an SNP). In the Taiwanese population, the deletion allele frequency is more than 0.5, and therefore the variant allele or minor allele is the insertion allele (gain in Table 1).

^*P values for Hardy–Weinberg equilibrium in AF (left-sided value in the top row) and NSR (right-sided value in the top row) populations, and comparison of genotype distribution between AF and NSR populations (bottom row).

^†D/D, homozygous deletion or copy number=0; D/I, heterozygous deletion or insertion or copy number=1; I/I, homozygous insertion or copy number=2.